This invention generally relates to electro-surgery, electro-cauterization and electro-coagulation of tissue in the body in combination with other forms of therapy using catheters. Specifically, this invention relates to an apparatus for performing electrosurgery, electrocauterization and electrocoagulation of tissue through a working channel of an endoscope.
Numerous medical procedures involve making an incision in body tissue and controlling any consequent bleeding. When performing these procedures, it is very important to minimize both tissue trauma during incision and the time required to stop internal bleeding. Minimally invasive or least invasive surgical techniques, such as laparoscopic, endoscopic, or arthroscopic techniques, are often used because body tissue is usually traumatized less by those techniques than by more invasive conventional techniques. Electrosurgical methodologies, often used in conjunction with the minimally or least invasive techniques, allow the making of an incision and the stopping or stemming of bleeding with less attendant tissue trauma and greater control than do conventional modalities.
A physician has several medical instruments in his or her armamentarium for making an incision and stemming consequent bleeding. In accordance with one modality that is particularly suited for application in the gastrointestinal tract, a physician initially positions a flexible endoscope in the patient with its distal end proximate to an incision site, and inserts a device for making an incision through a working channel of the endoscope to the incision site. The physician can also insert an irrigator through a working channel in the endoscope to clear the area by administering water or saline solution as a precursor to any attempts to make an incision or stop bleeding.
If the instrument being used for irrigation is like the Gold Probe(trademark) hemostat manufactured by Boston Scientific Corporation, the assignee of this invention, the physician can then cauterize a bleeding vessel using a distally positioned hemostat. Such instruments are constructed to be employed through a working channel of an endoscope to seal potential bleeding sites as in the gastrointestinal tract. Alternatively, the physician can retract the irrigating catheter and insert an elongated needle through the endoscope to inject a vaso-constrictor into the vessel to slow hemorrhaging. Then the physician can remove the elongated needle and reinsert the hemostat to finish the operation.
Some hemostats use mono-electropolar electrodes in which one electrode is carried by a catheter to a site while the other electrode is an exterior ground plate placed in or on a patient. The above-mentioned Gold Probe(trademark) hemostat is an example of a device that supplies a suitable current density and wave form of radio frequency energy to perform electro-coagulation or electro-cauterization. It utilizes a catheter with a bipolar electrode assembly located on a flexible shaft formed of a ceramic cylinder having a hemispherical end. The ceramic tip includes a pair of spaced gold spiral electrodes applied to its cylindrical surface and domed end. RF energy applied to the electrodes produces a current through adjacent tissue that heats and cauterizes the hemorrhaging vessel which is contacted by the tip of the catheter.
Physicians often use different catheters to perform different functions. For example, physicians will often use one catheter to make an incision and another to perform hemostasis and irrigation. The exchange of catheters to provide different functions extends the time to complete therapy, increases the risk to the patient and also increases patient discomfort. Consequently, physicians have to weigh the time, complexity and benefits of interchanging single or dual purpose catheters to change treatment modalities against whatever disadvantage may result by working with a single catheter.
U.S. Pat. No. 5,336,222, the contents of which are incorporated herein, discloses an integrated catheter assembly for enabling diverse in situ therapies which includes a catheter with an irrigation fluid lumen, a distal tip portion that acts as a hemostat and a needle for injection therapy.
In accordance with this invention, an integrated catheter assembly that enables a physician to utilize diverse in situ therapy modalities at selected tissue sites includes a catheter, an electrode tip and an electrode cutting wire. A lumen extends from a proximal end to a distal end of the catheter structure to provide a passage from a location externally of the patient to the tissue being treated. The bipolar electrode structure attaches to the distal end of the catheter structure and provides hemostatic therapy to selected tissue.
The electrode structure additionally has a central lumen aligned with the catheter lumen for enabling the transfer of irrigation fluids to tissue being treated. The cutting wire structure is electrically isolated from the electrode tip and extends from a proximal end externally of the patient through the lumens in the catheter and the electrode structure for axially displacement relative to the catheter and electrode structures. The cutting wire can be extended distally beyond and can be retracted proximally of a distal end surface of the electrode tip.
In an exemplary embodiment of a catheter assembly according to the present invention, a distal end of the cutting wire includes a substantially planar tip. The planar tip may be formed to achieve both a retracted, substantially circular configuration for insertion through an endoscope and for insertion of the endoscope through a lumen, and an extended, substantially planar configuration for use. The planar tip may further include bipolar circuitry on at least one face.